An Investigation on Duplex Nucleation in AZ91 Magnesium Alloy and Its Influence on High Temperature Mechanical Properties

2018 ◽  
Vol 140 (4) ◽  
Author(s):  
A. Saber ◽  
R. Haghayeghi ◽  
H. Najafi ◽  
Peiman Shahbeigi-Roodposhti
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Grain Refinement ◽  
Al Alloy ◽  
Grain Refiner ◽  
Az91 Magnesium Alloy ◽  
High Temperature Mechanical Properties ◽  
Nucleation Sites ◽  
Refinement Mechanism ◽  
Carbon Inoculation

The grain refinement of Mg–Al alloy AZ91 via carbon inoculation, including the significant role of Mn in advanced nucleation, was analyzed, and the corresponding mechanical properties and aging behavior were investigated. To this end, various amounts of C were added into the liquid at the desired temperatures. Al8Mn5 particles, which are suitable nucleation sites for α-Mg, were identified as the primary grain refiners. In situ particle formation, along with appropriate wetting and a suitable orientation relationship (OR), facilitated the grain refinement mechanism. Al4C3 particles contributed to heterogeneous nucleation by providing suitable Al8Mn5 nucleation sites. Mn removal resulted in poor grain refinement in the Mg–Al alloy. The Hall–Petch relationship, high-temperature tensile behavior, and aging mechanism of the samples refined by 1 wt % C addition (as the best grain refiner) are discussed and compared with industrial practice.

The Effect of Microalloying B on the High Temperature Mechanical Properties of Ti3Al

1988 ◽  
Vol 133 ◽  
Author(s):  
Joseph W. Newkirk ◽  
Gerald B. Feldewerth
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Tensile Properties ◽  
Grain Refinement ◽  
High Temperature Mechanical Properties ◽  
High Temperature Tensile ◽  
High Temperature Tensile Properties

ABSTRACTThe effect of adding boron to Ti3Al on the microstructure and high temperature tensile properties has been studied. Boron caused a large grain refinement that dominated the tensile properties at all temperatures. Particles of Ti2B were found in all of the boron containing alloys. TiB was found only at concentrations of 0.1% B or more.

scholarly journals Study on the Relationship between High Temperature Mechanical Properties and Precipitates Evolution of 7085 Al Alloy after Long Time Thermal Exposures

Metals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1483
Author(s):  
Jinxin Zang ◽  
Pan Dai ◽  
Yanqing Yang ◽  
Shuai Liu ◽  
Bin Huang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Electrical Conductivity ◽  
High Temperature ◽  
Tensile Properties ◽  
Volume Fraction ◽  
Al Alloy ◽  
Strengthening Effect ◽  
Nano Scale ◽  
High Temperature Mechanical Properties ◽  
The Relationship

The requirement for 7085 Al alloy as large airframe parts has been increasing due to its low quenching sensitivity and high strength. However, the relationship between high temperature mechanical properties and the evolution of precipitates in hot environments is still unclear. In this work, thermal exposure followed by tensile tests were conducted on the 7085 Al alloy at various temperatures (100 °C, 125 °C, 150 °C and 175 °C). Variations of hardness, electrical conductivity and tensile properties were investigated. The evolution of the nano scale precipitates was also quantitatively characterized by transmission electron microscopy (TEM). The results show that the hardness and electrical conductivity of the alloy are more sensitive to the temperature than to the time. The strength decreases continuously with the increase of temperature due to the transformation from η′ to η phase during the process. Furthermore, the main η phase in the alloy transformed from V3 and V4 to V1 and V2 variants when the temperature was 125 °C. Additionally, with increasing the temperature, the average precipitate radius increased, meanwhile the volume fraction and number density of the precipitates decreased. The strengthening effect of nano scale precipitates on tensile properties of the alloy was calculated and analyzed.

TEM Studies of Grain Boundary Films in Si3N4 Ceramics

1991 ◽  
Vol 49 ◽  
pp. 930-931
Author(s):  
H.-J. Kleebe ◽  
J.S. Vetrano ◽  
J. Bruley ◽  
M. Rühle
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Silicon Nitride ◽  
Hot Isostatic Pressing ◽  
Amorphous Film ◽  
Liquid Phase Sintering ◽  
Second Phase ◽  
High Temperature Mechanical Properties ◽  
Triple Points ◽  
Boundary Films

It is expected that silicon nitride based ceramics will be used as high-temperature structural components. Though much progress has been made in both processing techniques and microstructural control, the mechanical properties required have not yet been achieved. It is thought that the high-temperature mechanical properties of Si3N4 are limited largely by the secondary glassy phases present at triple points. These are due to various oxide additives used to promote liquid-phase sintering. Therefore, many attempts have been performed to crystallize these second phase glassy pockets in order to improve high temperature properties. In addition to the glassy or crystallized second phases at triple points a thin amorphous film exists at two-grain junctions. This thin film is found even in silicon nitride formed by hot isostatic pressing (HIPing) without additives. It has been proposed by Clarke that an amorphous film can exist at two-grain junctions with an equilibrium thickness.

BERYLCO NICKEL ALLOY 440

Alloy Digest ◽  
1975 ◽  
Vol 24 (9) ◽  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Nickel Alloy ◽  
High Strength ◽  
Heat Treating ◽  
Electronic Components ◽  
High Temperature Mechanical Properties ◽  
Temperature Performance ◽  
Solution Treated ◽  
Complex Shapes

Abstract BERYLCO NICKEL ALLOY 440 is an age-hardenable nickel-beryllium-titanium alloy that offers high strength, excellent spring properties outstanding formability, good high-temperature mechanical properties, and resistance to corrosion and fatigue. Complex shapes can be produced in the solution-treated (soft) condition and then aged to a minimum tensile strength of 215,500 psi. It is used for mechanical and electrical/electronic components in the temperature range -320 to 800 F. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, joining, and surface treatment. Filing Code: Ni-94. Producer or source: Kawecki Berylco Industries Inc.. Originally published September 1964, revised September 1975.

HASTELLOY ALLOY S

Alloy Digest ◽  
1973 ◽  
Vol 22 (1) ◽  
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Heat Treating ◽  
High Temperature Alloy ◽  
Excellent Thermal Stability ◽  
Cabot Corporation ◽  
High Temperature Mechanical Properties ◽  
Temperature Performance ◽  
Resistance To Oxidation ◽  
Nickel Base

Abstract HASTELLOY alloy S is a nickel-base high-temperature alloy having excellent thermal stability, good high-temperature mechanical properties and excellent resistance to oxidation up to 2000 F. This datasheet provides information on composition, physical properties, elasticity, and tensile properties as well as creep. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-184. Producer or source: Stellite Division, Cabot Corporation.

High temperature mechanical properties of Inconel 718 pulsed Nd–YAG laser welds

2006 ◽  
Vol 23 (1) ◽  
pp. 29-37 ◽  
Author(s):  
G.D. Janaki Ram ◽  
A. Venugopal Reddy ◽  
K. Prasad Rao ◽  
G. Madhusudhan Reddy
Keyword(s):  
Mechanical Properties ◽  
High Temperature ◽  
Inconel 718 ◽  
Yag Laser ◽  
High Temperature Mechanical Properties ◽  
Laser Welds

scholarly journals The Influence of La and Ce on Microstructure and Mechanical Properties of an Al-Si-Cu-Mg-Fe Alloy at High Temperature

Metals ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 384
Author(s):  
Andong Du ◽  
Anders E. W. Jarfors ◽  
Jinchuan Zheng ◽  
Kaikun Wang ◽  
Gegang Yu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
High Temperature ◽  
Intermetallic Phases ◽  
High Temperature Strength ◽  
Thermal Expansion Mismatch ◽  
Strengthening Mechanisms ◽  
High Temperature Mechanical Properties ◽  
Minor Contribution ◽  
A Minor

The effect of lanthanum (La)+cerium (Ce) addition on the high-temperature strength of an aluminum (Al)–silicon (Si)–copper (Cu)–magnesium (Mg)–iron (Fe)–manganese (Mn) alloy was investigated. A great number of plate-like intermetallics, Al11(Ce, La)3- and blocky α-Al15(Fe, Mn)3Si2-precipitates, were observed. The results showed that the high-temperature mechanical properties depended strongly on the amount and morphology of the intermetallic phases formed. The precipitated tiny Al11(Ce, La)3 and α-Al15(Fe, Mn)3Si2 both contributed to the high-temperature mechanical properties, especially at 300 °C and 400 °C. The formation of coarse plate-like Al11(Ce, La)3, at the highest (Ce-La) additions, reduced the mechanical properties at (≤300) ℃ and improved the properties at 400 ℃. Analysis of the strengthening mechanisms revealed that the load-bearing mechanism was the main contributing mechanism with no contribution from thermal-expansion mismatch effects. Strain hardening had a minor contribution to the tensile strength at high-temperature.

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